4 ms·

OP is topologically equivalent to a bagel (disregarding nostrils) https://en.wikipedia.org/wiki/Eustachian_tube https://en.wikipedia.org/wiki/Eustachian_tube

• vacri 10y ago
  The eustachian tube is sealed, unless you have a hole in your eardrum.
  • stephenboyd 10y ago
    There's also the nasolacrimal duct to consider. Other than those little details, one of my favorite insights from studying biology is that almost all animals are basically tubes with accessory organs attached, deuterostomes and protostomes.
    • trhway 10y ago
      https://en.wikipedia.org/wiki/File:Protovsdeuterostomes.svg https://en.wikipedia.org/wiki/File:Protovsdeuterostomes.svg https://en.wikipedia.org/wiki/Protostome https://en.wikipedia.org/wiki/Protostome : "In animals at least as complex as earthworms, the embryo forms a dent on one side, the blastopore, which deepens to become the archenteron, the first phase in the growth of the gut. In deuterostomes, the original dent becomes the anus while the gut eventually tunnels through to make another opening, which forms the mouth. The protostomes were so named because it used to be thought that in their embryos the dent formed the mouth while the anus was formed later, at the opening made by the other end of the gut."